This invention relates to a precolumn for a chromatography column in cartridge form which is packed with sorbent and has been provided with frit and sealing elements.
The chromatography columns used, in particular for high pressure liquid chromatography, are in general stainless steel column tubes which have been provided at both ends with screw fittings and capillary connection points for introducing and discharging eluent.
Of late, there has been a trend towards using column cartridges which have no screw fittings, but where the sorbent-packed column tube, which is sealed with frit and sealing elements, is clamped either in a cartridge holder as described for example in DOS No. 2,930,962, DOS No. 3,021,306 or U.S. Pat. No. 4,283,280, or in a column-clamping device as described in DOS No. 3,143,075. To protect the actual separat-separating column from soiling and blocking, frequently a generally very short precolumn is additionally inserted upstream thereof.
These precolumns are generally made of the same material and with the same diameter as the separating column and, like the latter, are provided with frit elements and seals, i.e., are thus constructed like the separating columns themselves, except for the fact that the precolumns are much shorter.
Since the precolumns, on account of their function, serve as traps for soil particles and contaminants which are bonded irreversibly to the sorbent and therefore must frequently be replaced, their elaborate and costly finish leads to a considerable financial burden on the user.
On the other hand, however, the precolumn must meet the same high requirements concerning stability, pressure load limit, tightness and dimensional accuracy as the separating column itself, so that in this area, despite the need for a less costly design of precolumns, no savings in terms of material and finish appeared possible.